Taylor series

How do i show that B_{x}(x+dx,y,z)-B_{x}(x,y,z)\approx \frac{\partial B_{x}(x,y,z)}{\partial x} dx
using a Taylor series to the first term. Using a Taylor series does B(x) = B(a) + B'(a)(x-a)? In that case what would B(x+dx) be and how can i obtain the desired result from this? Thanks in advance

I take it you mean [tex]B_x(x+dx,y,z)- B_x(x,y,z)= \frac{\partial B_x}{/partial dx}dxdydz[/tex]. I also assume that this is the x-component of a 3-vector.

You can't "prove" it- it's not true- except approximately which is what is intended here. The "Taylor series to the first term" is just the tangent approximation to Bx. Yes, at any given (x0, y0, z0) that is [tex]B_x(x_0,y_0,z_0)+ \frac{\partial B_0}{\partial x}(x_0,y_0,z_0)*(x- x_0)+ +\frac{\partial B_0}{\partial y}(x_0,y_0,z_0)*(y- y_0)+\frac{\partial B_0}{\partial z}(x_0,y_0,z_0)*(z- z_0)[/tex].